The _Excursion_ appeared in 1814, and in the course of the next year Wordsworth republished his minor poems, so arranged as to indicate the faculty of the mind which he considered to have been predominant in the composition of each. To most readers this disposition has always seemed somewhat arbitrary; and it was once suggested to Wordsworth that a chronological arrangement would be better. The manner in which Wordsworth met this proposal indicated the limit of his absorption in himself--his real desire only to dwell on his own feelings in such a way as might make them useful to others. For he rejected the plan as too egotistical--as emphasizing the succession of moods in the poet's mind, rather than the lessons which those moods could teach. His objection points, at any rate, to a real danger which any man's simplicity of character incurs by dwelling too attentively on the changing phases of his own thought. But after the writer's death the historical spirit will demand that poems, like other artistic products, should be disposed for the most part in the order of time. In a Preface to this edition of 1815, and a Supplementary Essay, he developed the theory on poetry already set forth in a well-known preface to the second edition of the _Lyrical Ballads_. Much of the matter of these essays, received at the time with contemptuous aversion, is now accepted as truth; and few compositions of equal length contain so much of vigorous criticism and sound reflection. It is only when they generalize too confidently that they are in danger of misleading us; for all expositions of the art and practice of poetry must necessarily be incomplete. Poetry, like all the arts, is essentially a "mystery." Its charm depends upon qualities which we can neither define accurately nor reduce to rule nor create again at pleasure. Mankind, however, are unwilling to admit this; and they endeavour from time to time to persuade themselves that they have discovered the rules which will enable them to produce the desired effect. And so much of the effect _can_ thus be reproduced, that it is often possible to believe for a time that the problem has been solved. Pope, to take the instance which was prominent in Wordsworth's mind, was, by general admission, a poet. But his success seemed to depend on imitable peculiarities; and Pope's imitators were so like Pope that it was hard to draw a line and say where they ceased to be poets. At last, however, this imitative school began to prove too much. If all the insipid verses which they wrote were poetry, what was the use of writing poetry at all? A reaction succeeded, which asserted that poetry depends on emotion and not on polish; that it consists precisely in those things which frigid imitators lack. Cowper, Burns, and Crabbe, (especially in his _Sir Eustace Grey_), had preceded Wordsworth as leaders of this reaction. But they had acted half unconsciously, or had even at